Where a number n of read attempts are required to successfully read a data sector, with the first n-1 attempts returning a disk drive read error, the number of attempts required is compared to a predefined threshold selected to indicate that the sector is unreliable and is in danger of becoming completely unrecoverable. If the threshold number of attempts is not exceeded, the sector is presumed to still be good and no further action need be taken. If the threshold number of attempts was equaled or exceeded, however, the unreliable or failing sector is relocated to a reserved replacement sector, with the recovered data written to the replacement sector. The failing data sector is remapped to the replacement sector, which becomes a fully functional substitute for the failing sector for future reads and writes while preserving the original user data. Data within a failing sector is thus preserved before the sector becomes completely unrecoverable.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of employing relocated sectors, comprising: detecting a disk access operation to a disk storage device in an operating system component managing the disk storage device; checking a defect map table identifying relocated sectors within the disk storage device, wherein said relocated sectors are in replacement sectors reserved by said operating system; and responsive to determining that a target sector for the detected disk access operation has been relocated, substituting an identifier for a replacement sector to which the target sector was relocated for an identifier for the relocated target sector within the detected disk access operation.
2. The method of claim 1 , wherein the step of detecting a disk access operation to a disk storage device in an operating system component managing the disk storage device further comprises: detecting a read or write including the identifier for the target sector.
3. The method of claim 2 , wherein the step of checking a defect map table identifying relocated sectors within the disk storage device further comprises: comparing the identifier for the target sector to identifiers of relocated sectors within entries in the defect map table.
4. The method of claim 1 , wherein the step of substituting an identifier for a replacement sector to which the target sector was relocated for an identifier for the relocated target sector within the detected disk access operation further comprises: substituting a logical block number for the replacement sector for a logical block number for the target sector within the disk access operation.
5. A system for employing relocated sectors, comprising: a disk storage device; a memory containing a defect map identifying relocated sectors on the disk storage device, wherein said relocated sectors are in replacement sectors reserved by an operating system; and a processor coupled to the disk storage device and the memory and executing a disk access process including: detecting a disk access operation to the disk storage device in said operating system component managing the disk storage device; checking the defect map table; and responsive to determining that a target sector for the detected disk access operation has been relocated, substituting an identifier for a replacement sector to which the target sector was relocated for an identifier for the relocated target sector within the detected disk access operation.
6. The system of claim 5 , wherein the disk access process detects a read or write including the identifier for the target sector.
7. The system of claim 6 , wherein the disk access process compares the identifier for the target sector to identifiers of relocated sectors within entries in the defect map table.
8. The system of claim 5 , wherein the disk access process substitutes a logical block number for the replacement sector for a logical block number for the target sector within the disk access operation.
9. A computer program product within a computer usable medium for employing relocated sectors, comprising: instructions for detecting a disk access operation to a disk storage device in an operating system component managing the disk storage device; instructions for checking a defect map table identifying relocated sectors within the disk storage device, wherein said relocated sectors are replacement sectors reserved by said operating system; and instructions, responsive to determining that a target sector for the detected disk access operation has been relocated, for redirecting the disk access operation to a replacement sector to which the target sector was relocated.
10. The computer program product of claim 9 , wherein the instructions for detecting a disk access operation to a disk storage device in an operating system component managing the disk storage device further comprise: instructions for detecting a read or write including the identifier for the target sector.
11. The computer program product of claim 10 , wherein the instructions for checking a defect map table identifying relocated sectors within the disk storage device further comprise: instructions for comparing the identifier for the target sector to identifiers of relocated sectors within entries in the defect map table.
12. The computer program product of claim 9 , wherein the instructions for redirecting the disk access operation to a replacement sector to which the target sector was relocated further comprise: instructions for substituting a logical block number for the replacement sector for a logical block number for the target sector within the disk access operation.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
March 1, 2001
July 30, 2002
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